Lyme disease is a bacterial infection that can sometimes cause Lyme carditis. This condition commonly involves heart block. Symptoms can include lightheadedness, shortness of breath, chest pain, and fainting.

Lyme carditis is a complication of Lyme disease. It involves swelling of the heart and often causes heart block, which is when disruption to the atrioventricular node causes abnormal heart activity.

This article looks at Lyme disease and heart problems, as well as the treatment, recovery, and outlook for Lyme carditis.

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About 1–5% of people diagnosed with Lyme disease will develop Lyme carditis. Lyme carditis is a complication of Lyme disease that affects the heart.

Most of the time, Lyme carditis involves the atrioventricular (AV) node. The AV node regulates how the heart beats. Lyme carditis can therefore cause heart block.

Heart block is when the AV node makes the heart beat abnormally. It could make the heart beat too slowly, or with an irregular rhythm.

Less commonly, Lyme carditis causes other heart problems. These include:

The Centers for Disease Control and Prevention (CDC) lists some common Lyme carditis symptoms.

These include symptoms of heart block, such as:

People with Lyme carditis may also experience symptoms of Lyme disease, including:

Anyone with symptoms of Lyme disease or Lyme carditis should seek medical advice.

Scientists define Lyme disease as an infection from the Borrelia burgdorferi bacterium. This bacterium is a tick-borne pathogen. Infected ticks can spread it when they feed on human hosts.

Lyme carditis can occur if the Borrelia burgdorferi enters into heart tissues. Scientists remain uncertain about how this causes heart problems.

The cause of heart block could be an autoimmune inflammatory process that may arise within the AV node.

Researchers continue to investigate the exact causes of Lyme carditis.

Possible risk factors for Lyme disease

In 2015, 95% of the people recorded to have Lyme disease in the United States were in the Northeast, mid-Atlantic, and upper Midwest states. People in these regions may be more likely to develop Lyme disease from a tick bite.

Additionally, Lyme disease mostly affected males between the ages of 5–9 and 45–59 years, as of 2015.

Lyme disease is more common in young adult males, with a male-to-female ratio of roughly 3-to-1.

When an individual has symptoms of Lyme carditis, doctors may investigate further.

A study in the Journal of the American College of Cardiology discusses the ideal diagnostic approach for Lyme carditis.

There are two main steps to diagnosing this condition. The first step is detecting heart block. The second step is detecting Lyme disease.

Doctors can use an electrocardiogram (EKG) to determine whether an individual has heart block. An EKG measures electrical impulses within the heart, allowing doctors to spot any abnormal activity. Doctors can also use this to gauge the severity of heart block.

If an individual does have heart block, doctors will try to determine whether they also have Lyme disease.

This involves checking for factors that increase the probability that someone has Lyme disease, including:

  • Lyme disease symptoms
  • the presence of a tick bite
  • pursuing outdoor activities
  • being male
  • being less than 50 years old

If an individual has the correct number or combination of such factors, doctors will recommend blood tests for Lyme disease.

As a 2019 study explains, the optimal Lyme carditis treatment has multiple aspects. These include the following steps:

  • Initial antibiotic phase: Doctors will recommend starting antibiotics as soon as they recommend Lyme disease blood tests.
  • Pre-diagnosis cardiac interventions: Before the doctor receives blood test results, they will check whether their patient’s heart block is serious. If it is not, they will continually monitor their patient’s heart activity. If it is serious and causes symptoms, such as chest pain, fainting, or low blood pressure, they may recommend a temporary pacemaker.
  • Post-diagnosis antibiotic phase: If the blood tests indicate Lyme disease, antibiotic treatment will continue. This should include 10–14 days of intravenous (IV) antibiotics, followed by 4–7 days of oral antibiotics.

Doctors will monitor heart function throughout treatment and make further recommendations 14 days post-admission.

Lyme carditis usually resolves after antibiotic therapy. Doctors should inform individuals who require a permanent pacemaker about pacemaker safety.

According to a 2016 review, most people completely recover from Lyme disease.

However, some individuals may experience post-treatment symptoms that last for several months or even years. These symptoms include:

  • tiredness
  • cognitive problems
  • musculoskeletal pain

For this reason, recovery will look very different for each person.

It is not always possible to eliminate the risk of Lyme disease.

However, the CDC provides some useful tips to make Lyme disease less likely. These include:

  • treating clothes and outdoor gear with 0.5% permethrin products
  • using insect repellents
  • sticking to the center of trails
  • avoiding higher grasses
  • checking clothing, gear, and pets for ticks

The CDC also recommends showering after returning from the outdoors. After showering, an individual should check their whole body for ticks.

According to a recent review, scientists consider people with Lyme carditis to have a generally positive outlook.

Most people with Lyme carditis have a treatable form of the condition. Even in people with more serious cases of heart block, most with Lyme carditis completely recover within an average of 6 days.

It is very uncommon for persistent heart problems to arise from Lyme carditis. It is also extremely rare for people to die from this condition.

This section answers some frequently asked questions about Lyme disease and heart problems.

How long does it take for Lyme disease to affect your heart?

According to a 2022 review, if Lyme disease affects the heart, it does so within several weeks or months of the initial infection.

If a person notices a tick bite, they should monitor themselves closely for any symptoms of Lyme disease. These include:

  • a growing bull’s-eye rash
  • body aches
  • fever

Symptoms of a heart problem resulting from Lyme disease may include fainting, chest pains, and heart palpitations. This could indicate Lyme carditis.

If a person suspects Lyme disease or Lyme carditis, they should contact a medical professional as soon as possible.

Can Lyme cause permanent heart damage?

Lyme disease can affect the heart, and professionals call this Lyme carditis. Lyme carditis is unlikely to cause permanent heart damage.

In the vast majority of people with Lyme carditis, heart block from Lyme disease goes away with treatment.

Does Lyme carditis show up on an EKG?

Yes, complications from Lyme disease — such as heart block — do show up on EKGs. This way, doctors can diagnose a person with Lyme carditis and start treatment.

Lyme carditis is a relatively uncommon complication of Lyme disease.

It usually causes problems with the atrioventricular node. In most cases, treatment for Lyme carditis is very effective, and people can make a full recovery.

A person can take steps to prevent tick bites and Lyme disease by avoiding tall grass, sticking to public trails, and always checking their body for tick bites after outdoor outings.